You can see a recollection of commands on a linux system by using the history command. I would like to share with you a good trick to not only see the command, but also the timestamp it was executed. This is particularly useful for auditing. You simply need to set the environmental variable as follows:
export HISTTIMEFORMAT="%F %T "
Now, history will display commands as follows:
1476 2012-09-13 06:25:59 mysql
1477 2012-09-13 06:25:59 exit
1478 2012-09-13 06:26:02 history | less